Desorption kinetics and mobility of some radionuclides in sediments

Journal Article · Sat Dec 01 04:00:00 UTC 1990 · Health Physics; (USA)

DOI:https://doi.org/10.1097/00004032-199012000-00011· OSTI ID:6278655

Fukui, M ^[1]

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1. Kyoto Univ., Osaka (Japan)

The desorption kinetics of five radionuclides, 85Sr, 137Cs, 60Co, 54Mn, and 65Zn, were studied for several coastal sediments, a few limnetic sediments, and one subsoil, using various aqueous solutions for extraction in batch systems. In a 2-wk desorption experiment, greater than 90% of most radionuclides sorbed were extracted by 6N-HCl, whereas in 1N-HCl approximately 30% of the 137Cs was retained within the sediments and a soil due to its fixation following intraparticle diffusion. For longer desorption periods (6 wk), reversible sorption with sediments could be seen for the 137Cs compared with the other four radionuclides in seawater. The EDTA-2Na solution extracted greater than 70% of 65Zn, 54Mn, and 60Co, and the ammonium oxalate extracted greater than 60% of 54Mn and 60Co. Readily exchangeable cations extracted by ammonium acetate were greater than 80% for 85Sr, approximately 50% for 137Cs, and 40% for 60Co and 54Mn. Many of the distribution coefficients for these radionuclides in coastal sediments obtained by desorption experiments were one order of magnitude or more larger than those obtained by the adsorption experiments. For 85Sr, larger-than-expected distribution coefficients were obtained in the desorption experiments, an indication of the irreversible formation of metal-oxyhydroxides during a slow reaction. Using batch and column diffusion experiments, it was recognized that 60Co and 54Mn are less strongly associated with coastal sediments under suboxic conditions, and their migration rates are greater in deeper layers of sediment than in the top layer, an indication that a single Kd model is inappropriate to forecast the behavior of radionuclides near sediment surface layers.

• OSTI ID: 6278655
• Journal Information: Health Physics; (USA), Journal Name: Health Physics; (USA) Vol. 59:6; ISSN 0017-9078; ISSN HLTPA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540330* -- Environment
Aquatic-- Radioactive Materials Monitoring & Transport-- (1990-)
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CESIUM 137
CESIUM ISOTOPES
COASTAL WATERS
COBALT 60
COBALT ISOTOPES
DAYS LIVING RADIOISOTOPES
DESORPTION
ELECTRON CAPTURE RADIOISOTOPES
ENVIRONMENTAL TRANSPORT
EVEN-ODD NUCLEI
EXTRACTION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ION EXCHANGE
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MANGANESE 54
MANGANESE ISOTOPES
MASS TRANSFER
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
POLLUTION
RADIOISOTOPES
RADIONUCLIDE MIGRATION
SEDIMENTS
SEPARATION PROCESSES
SOLVENT EXTRACTION
STRONTIUM 85
STRONTIUM ISOTOPES
SURFACE WATERS
WATER POLLUTION
YEARS LIVING RADIOISOT
YEARS LIVING RADIOISOTOPES
ZINC 65
ZINC ISOTOPES